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SPARQL (pronounced "sparkle" ^[1]) is an RDF query language; its name is a recursive acronym that stands for SPARQL Protocol and RDF Query Language. It is undergoing standardization by the RDF Data Access Working Group (DAWG) of the World Wide Web Consortium. On the track towards status of W3C recommendation, it was released as a Candidate Recommendation in April 2006, but returned to Working Draft status in October 2006, due to two open issues. ^[2] In June 2007, SPARQL advanced to Candidate Recommendation once again. ^[3] On 12th November 2007 the status of SPARQL changed into Proposed Recommendation. ^[4]

SPARQL allows for a query to consist of triple patterns, conjunctions, disjunctions, and optional patterns.^[5]

Several implementations for multiple programming languages exist. "SPARQL will make a huge difference" according to Sir Tim Berners-Lee in a May 2006 interview. ^[6]

Example

The following simple SPARQL query returns all African capitals:

PREFIX abc: <http://example.com/exampleOntology#>
SELECT ?capital ?country
WHERE {
  ?x abc:cityname ?capital ;
     abc:isCapitalOf ?y.
  ?y abc:countryname ?country ;
     abc:isInContinent abc:africa.
}

Variables are indicated by a "?" or "$" prefix. Bindings for ?capital and the ?country will be returned.

The SPARQL query processor will search for sets of triples that match these four triple patterns, binding the variables in the query to the corresponding parts of each triple. Important to note here is the "property orientation" (class matches can be conducted solely through class-attributes / properties - see Duck_typing)

To make queries concise, SPARQL allows the definition of prefixes and base URIs in a fashion similar to Turtle. In this query, the prefix "abc" stands for “http://example.com/exampleOntology#”.

References

^ Jim Rapoza (May 2, 2006). "SPARQL Will Make the Web Shine". eWeek. Retrieved 2007-01-17.
^ Eric Prud'hommeaux, W3C; Andy Seaborne, Hewlett-Packard Laboratories (4 October 2006). "SPARQL Query Language for RDF : W3C Working Draft". Retrieved 2007-01-17.{{cite web}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
^ http://www.w3.org/blog/SW/2007/06/15/sparql_is_a_candidate_recommendation
^ http://www.w3.org/News/2007#item247
^ "XML and Web Services In The News". xml.org. 6 October 2006. Retrieved 2007-01-17.
^ Reuters (22 May 2006). "Berners-Lee looks for Web's big leap". zdnet.co.uk. Retrieved 2007-01-17. {{cite news}}: |author= has generic name (help)

External links

Specs, articles, and tutorials

Tool support

AllegroGraph RDFStore
Protégé
RDF api for PHP
TopBraid Composer
Virtuoso Universal Server
Internet Business Logic A browser based system for writing and running rules in open vocabulary executable English [1]. The rules can be used to question a database of RDF triples, and the queries can include aggregations [2]. The system also automatically generates and runs SQL that would be too complex to write reliably by hand. There are explanations of the RDF and SQL results, in English, at the end-user level. Shared use of the system is free.

Public SPARQL query service endpoints

Various SPARQL use-case demos

This World Wide Web–related article is a stub. You can help Wikipedia by expanding it.

[1] Jim Rapoza (May 2, 2006). "SPARQL Will Make the Web Shine". eWeek. Retrieved 2007-01-17.

[WD-rdf-sparql-query-20061004-2] Eric Prud'hommeaux, W3C; Andy Seaborne, Hewlett-Packard Laboratories (4 October 2006). "SPARQL Query Language for RDF : W3C Working Draft". Retrieved 2007-01-17.{{cite web}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)

[3] ttp://www.w3.org/blog/SW/2007/06/15/sparql_is_a_candidate_recommendation

[4] ttp://www.w3.org/News/2007#item247

[5] "XML and Web Services In The News". xml.org. 6 October 2006. Retrieved 2007-01-17.

[6] Reuters (22 May 2006). "Berners-Lee looks for Web's big leap". zdnet.co.uk. Retrieved 2007-01-17. {{cite news}}: |author= has generic name (help)

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 * [http://www.topbraidcomposer.com TopBraid Composer]
 * [[Virtuoso Universal Server]]
+*'''Internet Business Logic'''  A browser based system for writing and running rules in open vocabulary executable English [http://www.reengineeringllc.com/]. The rules can be used to question a database of RDF triples, and the queries can include aggregations [http://www.reengineeringllc.com/demo_agents/RDFQueryLangComparison1.agent].  The system also automatically generates and runs SQL that would be too complex to write reliably by hand.  There are explanations of the RDF and SQL results, in English, at the end-user level.  Shared use of the system is free.
 ===Public SPARQL query service endpoints===